"Doc Ock", as he's sometimes called, has a harness with four super-strong mechanical arms, originally developed to assist him in his scientific research. In an accident, the apparatus became fused to his body, and he gained the ability to control the movement of the arms using his thoughts alone. The accident also drove him mad, and he turned to a life of crime. Later, the harness was surgically removed, but he was still able to control it mentally, even at a distance.
Though Doctor Octopus himself is not much to speak of physically, with his harness attached he is physically a match for Spider-Man.
Despite the obvious obstacles, Octavius was for a time on good terms with Peter Parker's Aunt May, who he first met in The Amazing Spider-Man Annual #1 (1964) when he abducted her and Peter's then-girlfriend Betty Brant to attract Spider-Man's attention.